@misc{LiebigSarhanPrietzeletal.2016,
  author    = {Liebig, Ferenc and Sarhan, Radwan Mohamed and Prietzel, Claudia Christina and Reinecke, Antje and Koetz, Joachim},
  title     = {"Green" gold nanotriangles: synthesis, purification by polyelectrolyte/micelle depletion flocculation and performance in surface-enhanced Raman scattering},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-394430},
  pages     = {33561 -- 33568},
  year      = {2016},
  abstract  = {The aim of this study was to develop a one-step synthesis of gold nanotriangles (NTs) in the presence of mixed phospholipid vesicles followed by a separation process to isolate purified NTs. Negatively charged vesicles containing AOT and phospholipids, in the absence and presence of additional reducing agents (polyampholytes, polyanions or low molecular weight compounds), were used as a template phase to form anisotropic gold nanoparticles. Upon addition of the gold chloride solution, the nucleation process is initiated and both types of particles, i.e., isotropic spherical and anisotropic gold nanotriangles, are formed simultaneously. As it was not possible to produce monodisperse nanotriangles with such a one-step procedure, the anisotropic nanoparticles needed to be separated from the spherical ones. Therefore, a new type of separation procedure using combined polyelectrolyte/micelle depletion flocculation was successfully applied. As a result of the different purification steps, a green colored aqueous dispersion was obtained containing highly purified, well-defined negatively charged flat nanocrystals with a platelet thickness of 10 nm and an edge length of about 175 nm. The NTs produce promising results in surface-enhanced Raman scattering.},
  language  = {en}
}
@article{KoetzKosmellaKulickeetal.2002,
  author    = {Koetz, Joachim and Kosmella, Sabine and Kulicke, Werner-Michael and Heinze, Thomas},
  title     = {Zum Einfluss des L{\"o}sungszustandes von Carboxymethylcellulosen auf das Strukturbildungsverhalten in kolloidalen Systemen},
  year      = {2002},
  language  = {de}
}
@article{SchusterKoetzJaegeretal.1996,
  author    = {Schuster, Ch. and Koetz, Joachim and Jaeger, Werner and Kulicke, Werner-Michael},
  title     = {Wechselwirkungen zwischen Kl{\"a}rschlammpartikeln und Polyelektrolyten},
  year      = {1996},
  language  = {de}
}
@article{vonReppertSarhanSteteetal.2016,
  author    = {von Reppert, Alexander and Sarhan, Radwan Mohamed and Stete, Felix and Pudell, Jan-Etienne and Del Fatti, N. and Crut, A. and Koetz, Joachim and Liebig, Ferenc and Prietzel, Claudia Christina and Bargheer, Matias},
  title     = {Watching the Vibration and Cooling of Ultrathin Gold Nanotriangles by Ultrafast X-ray Diffraction},
  series = {The journal of physical chemistry : C, Nanomaterials and interfaces},
  volume    = {120},
  journal   = {The journal of physical chemistry : C, Nanomaterials and interfaces},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1932-7447},
  doi       = {10.1021/acs.jpcc.6b11651},
  pages     = {28894 -- 28899},
  year      = {2016},
  abstract  = {We study the vibrations of ultrathin gold nanotriangles upon optical excitation of the electron gas by ultrafast X-ray diffraction. We quantitatively measure the strain evolution in these highly asymmetric nano-objects, providing a direct estimation of the amplitude and phase of the excited vibrational motion. The maximal strain value is well reproduced by calculations addressing pump absorption by the nanotriangles and their resulting thermal expansion. The amplitude and phase of the out-of-plane vibration mode with 3.6 ps period dominating the observed oscillations are related to two distinct excitation mechanisms. Electronic and phonon pressures impose stresses with different time dependences. The nanosecond relaxation of the expansion yields a direct temperature sensing of the nano-object. The presence of a thin organic molecular layer at the nanotriangle/substrate interfaces drastically reduces the thermal conductance to the substrate.},
  language  = {en}
}
@article{KoethAppelhansRobertsonetal.2011,
  author    = {Koeth, Anja and Appelhans, Dietmar and Robertson, Daniela and Tiersch, Brigitte and Koetz, Joachim},
  title     = {Use of weakly cationic dendritic glycopolymer for morphological transformation of phospholipid vesicles into tube-like networks},
  series = {Soft matter},
  volume    = {7},
  journal   = {Soft matter},
  number    = {22},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1744-683X},
  doi       = {10.1039/c1sm06439h},
  pages     = {10581 -- 10584},
  year      = {2011},
  abstract  = {Using cationic polyelectrolytes with different molecular architectures, only hyperbranched poly(ethyleneimine) with maltose shell is suited to tailor the morphological transformation of anionic vesicles into tube-like networks. The interaction features of those materials partly mimic biological features of tubular proteins in nature.},
  language  = {en}
}
@article{LiebigSarhanPrietzeletal.2018,
  author    = {Liebig, Ferenc and Sarhan, Radwan Mohamed and Prietzel, Claudia Christina and Th{\"u}nemann, Andreas F. and Bargheer, Matias and Koetz, Joachim},
  title     = {Undulated Gold Nanoplatelet Superstructures},
  series = {Langmuir},
  volume    = {34},
  journal   = {Langmuir},
  number    = {15},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0743-7463},
  doi       = {10.1021/acs.langmuir.7b02898},
  pages     = {4584 -- 4594},
  year      = {2018},
  abstract  = {Negatively charged flat gold nanotriangles, formed in a vesicular template phase and separated by an AOT-micelle-based depletion flocculation, were reloaded by adding a cationic polyelectrolyte, that is, a hyperbranched polyethylenimine (PEI). Heating the system to 100 degrees C in the presence of a gold chloride solution, the reduction process leads to the formation of gold nanoparticles inside the polymer shell surrounding the nanoplatelets. The gold nanoparticle formation is investigated by UV-vis spectroscopy, small-angle X-ray scattering, and dynamic light scattering measurements in combination with transmission electron microscopy. Spontaneously formed gold clusters in the hyperbranched PEI shell with an absorption maximum at 350 nm grow on the surface of the nanotriangles as hemispherical particles with diameters of similar to 6 nm. High-resolution micrographs show that the hemispherical gold particles are crystallized onto the {111} facets on the bottom and top of the platelet as well as on the edges without a grain boundary. Undulated gold nanoplatelet superstructures with special properties become available, which show a significantly modified performance in SERS-detected photocatalysis regarding both reactivity and enhancement factor.},
  language  = {en}
}
@article{RajuLiebigKlemkeetal.2020,
  author    = {Raju, Rajarshi Roy and Liebig, Ferenc and Klemke, Bastian and Koetz, Joachim},
  title     = {Ultralight magnetic aerogels from Janus emulsions},
  series = {RSC Advances},
  volume    = {10},
  journal   = {RSC Advances},
  number    = {13},
  publisher = {RSC Publishing},
  address   = {London},
  issn      = {2046-2069},
  doi       = {10.1039/c9ra10247g},
  pages     = {7492 -- 7499},
  year      = {2020},
  abstract  = {Magnetite containing aerogels were synthesized by freeze-drying olive oil/silicone oil-based Janus emulsion gels containing gelatin and sodium carboxymethylcellulose (NaCMC). The magnetite nanoparticles dispersed in olive oil are processed into the gel and remain in the macroporous aerogel after removing the oil components. The coexistence of macropores from the Janus droplets and mesopores from freeze-drying of the hydrogels in combination with the magnetic properties offer a special hierarchical pore structure, which is of relevance for smart supercapacitors, biosensors, and spilled oil sorption and separation. The morphology of the final structure was investigated in dependence on initial compositions. More hydrophobic aerogels with magnetic responsiveness were synthesized by bisacrylamide-crosslinking of the hydrogel. The crosslinked aerogels can be successfully used in magnetically responsive clean up experiments of the cationic dye methylene blue.},
  language  = {en}
}
@misc{RajuLiebigKlemkeetal.2020,
  author    = {Raju, Rajarshi Roy and Liebig, Ferenc and Klemke, Bastian and Koetz, Joachim},
  title     = {Ultralight magnetic aerogels from Janus emulsions},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
  number    = {828},
  doi       = {10.25932/publishup-44552},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-445522},
  pages     = {10},
  year      = {2020},
  abstract  = {Magnetite containing aerogels were synthesized by freeze-drying olive oil/silicone oil-based Janus emulsion gels containing gelatin and sodium carboxymethylcellulose (NaCMC). The magnetite nanoparticles dispersed in olive oil are processed into the gel and remain in the macroporous aerogel after removing the oil components. The coexistence of macropores from the Janus droplets and mesopores from freeze-drying of the hydrogels in combination with the magnetic properties offer a special hierarchical pore structure, which is of relevance for smart supercapacitors, biosensors, and spilled oil sorption and separation. The morphology of the final structure was investigated in dependence on initial compositions. More hydrophobic aerogels with magnetic responsiveness were synthesized by bisacrylamide-crosslinking of the hydrogel. The crosslinked aerogels can be successfully used in magnetically responsive clean up experiments of the cationic dye methylene blue.},
  language  = {en}
}
@article{LiebigSarhanPrietzeletal.2018,
  author    = {Liebig, Ferenc and Sarhan, Radwan Mohamed and Prietzel, Claudia Christina and Schmitt, Clemens Nikolaus Zeno and Bargheer, Matias and Koetz, Joachim},
  title     = {Tuned Surface-Enhanced raman scattering performance of undulated Au@Ag triangles},
  series = {ACS applied nano materials},
  volume    = {1},
  journal   = {ACS applied nano materials},
  number    = {4},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {2574-0970},
  doi       = {10.1021/acsanm.8b00570},
  pages     = {1995 -- 2003},
  year      = {2018},
  abstract  = {Negatively charged ultraflat gold nanotriangles (AuNTs) stabilized by the anionic surfactant dioctyl sodium sulfosuccinate (AOT) were reloaded with the cationic surfactant benzylhexadecyldimethylammonium chloride (BDAC). Because of the spontaneous formation of a catanionic AOT micelle/BDAC bilayer onto the surface of the reloaded AuNTs, a reduction of Ag+ ions leads to the formation of spherical silver nanoparticles (AgNPs). With increasing concentration of AgNPs on the AuNTs, the localized surface plasmon resonance (LSPR) is shifted stepwise from 1300 to 800 nm. The tunable LSPR enables to shift the extinction maximum to the wavelength of the excitation laser of the Raman microscope at 785 nm. Surface-enhanced Raman scattering (SERS) experiments performed under resonance conditions show an SERS enhancement factor of the analyte molecule rhodamine RG6 of 5.1 X 10(5), which can be related to the silver hot spots at the periphery of the undulated gold nanoplatelets.},
  language  = {en}
}
@article{LiebigMorenoThuenemannetal.2018,
  author    = {Liebig, Ferenc and Moreno, Silvia and Thuenemann, Andreas F. and Temme, Achim and Appelhans, Dietmar and Koetz, Joachim},
  title     = {Toxicological investigations of "naked" and polymer-entrapped AOT-based gold nanotriangles},
  series = {Colloids and surfaces : an international journal devoted to fundamental and applied research on colloid and interfacial phenomena in relation to systems of biological origin ; B, Biointerfaces},
  volume    = {167},
  journal   = {Colloids and surfaces : an international journal devoted to fundamental and applied research on colloid and interfacial phenomena in relation to systems of biological origin ; B, Biointerfaces},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0927-7765},
  doi       = {10.1016/j.colsurfb.2018.04.059},
  pages     = {560 -- 567},
  year      = {2018},
  abstract  = {Negatively charged ultrathin gold nanotriangles (AuNTs) were synthesized in a vesicular dioctyl sodium sulfosuccinate (AOT)/phospholipid-based template phase. These "naked" AuNTs with localized surface plasmon resonances in the NIR region at about 1300 nm and special photothermal properties are of particular interest for imaging and hyperthermia of cancerous tissues. For these kinds of applications the toxicity and the cellular uptake of the AuNTs is of outstanding importance. Therefore, this study focuses on the toxicity of "naked" AOT-stabilized AuNTs compared to polymer-coated AuNTs. Polymeric coating consisted of non-modified hyperbranched poly(ethyleneimine) (PEI), maltose-modified poly(ethyleneimine) (PEI-Mal) and heparin. The toxicological experiments were carried out with two different cell lines (embryonic kidney carcinoma cell line HEK293T and NK-cell leukemia cell line YTS). This study revealed that the heparin-coating of AuNTs improved biocompatibility by a factor of 50 when compared to naked AuNTs. Of note, the highest nontoxic concentration of the AuNTs coated with PEI and PEI-Mal is drastically decreased. Overall, this is mainly triggered by the different surface charges of polymeric coatings. Therefore, AuNTs coated with heparin were selected to carry out uptake studies. Their promising high biocompatibility and cellular uptake may open future studies in the field of biomedical applications. (C) 2018 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{BroekerRoskeVallerianietal.2019,
  author    = {Broeker, Nina K. and Roske, Yvette and Valleriani, Angelo and Stephan, Mareike Sophia and Andres, Dorothee and Koetz, Joachim and Heinemann, Udo and Barbirz, Stefanie},
  title     = {Time-resolved DNA release from an O-antigen-specific Salmonella bacteriophage with a contractile tail},
  series = {The journal of biological chemistry},
  volume    = {294},
  journal   = {The journal of biological chemistry},
  number    = {31},
  publisher = {American Society for Biochemistry and Molecular Biology},
  address   = {Bethesda},
  issn      = {1083-351X},
  doi       = {10.1074/jbc.RA119.008133},
  pages     = {11751 -- 11761},
  year      = {2019},
  abstract  = {Myoviruses, bacteriophages with T4-like architecture, must contract their tails prior to DNA release. However, quantitative kinetic data on myovirus particle opening are lacking, although they are promising tools in bacteriophage-based antimicrobial strategies directed against Gram-negative hosts. For the first time, we show time-resolved DNA ejection from a bacteriophage with a contractile tail, the multi-O-antigen-specific Salmonella myovirus Det7. DNA release from Det7 was triggered by lipopolysaccharide (LPS) O-antigen receptors and notably slower than in noncontractile-tailed siphoviruses. Det7 showed two individual kinetic steps for tail contraction and particle opening. Our in vitro studies showed that highly specialized tailspike proteins (TSPs) are necessary to attach the particle to LPS. A P22-like TSP confers specificity for the Salmonella Typhimurium O-antigen. Moreover, crystal structure analysis at 1.63 angstrom resolution confirmed that Det7 recognized the Salmonella Anatum O-antigen via an E15-like TSP, DettilonTSP. DNA ejection triggered by LPS from either host showed similar velocities, so particle opening is thus a process independent of O-antigen composition and the recognizing TSP. In Det7, at permissive temperatures TSPs mediate O-antigen cleavage and couple cell surface binding with DNA ejection, but no irreversible adsorption occurred at low temperatures. This finding was in contrast to short-tailed Salmonella podoviruses, illustrating that tailed phages use common particle-opening mechanisms but have specialized into different infection niches.},
  language  = {en}
}
@article{CouturierWischerhoffBerninetal.2016,
  author    = {Couturier, Jean-Philippe and Wischerhoff, Erik and Bernin, Robert and Hettrich, Cornelia and Koetz, Joachim and Sutterlin, Martin and Tiersch, Brigitte and Laschewsky, Andre},
  title     = {Thermoresponsive Polymers and Inverse Opal Hydrogels for the Detection of Diols},
  series = {Langmuir},
  volume    = {32},
  journal   = {Langmuir},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0743-7463},
  doi       = {10.1021/acs.langmuir.6b00803},
  pages     = {4333 -- 4345},
  year      = {2016},
  abstract  = {Responsive inverse opal hydrogels functionalized by boroxole moieties were synthesized and explored as sensor platforms for various low molar mass as well as polymeric diols and polyols, including saccharides, glycopolymers and catechols, by exploiting the diol induced modulation of their structural color. The underlying thermoresponsive water-soluble copolymers and hydrogels exhibit a coil-to-globule or volume phase transition, respectively, of the LCST-type. They were prepared from oligoethylene oxide methacrylate (macro)monomers and functionalized via copolymerization to bear benzoboroxole moieties. The resulting copolymers represent weak polyacids, which can bind specifically to diols within an appropriate pH window. Due to the resulting modulation of the overall hydrophilicity of the systems and the consequent shift of their phase transition temperature, the usefulness of such systems for indicating the presence of catechols, saccharides, and glycopolymers was studied, exploiting the diol/polyol induced shifts of the soluble polymers' cloud point, or the induced changes of the hydrogels' swelling. In particular, the increased acidity of benzoboroxoles compared to standard phenylboronic acids allowed performing the studies in PBS buffer (phosphate buffered saline) at the physiologically relevant pH of 7.4. The inverse opals constructed of these thermo- and analyte-responsive hydrogels enabled following the binding of specific diols by the induced shift of the optical stop band. Their highly porous structure enabled the facile and specific optical detection of not only low molar mass but also of high molar mass diol/polyol analytes such as glycopolymers. Accordingly, such thermoresponsive inverse opal systems functionalized with recognition units represent attractive and promising platforms for the facile sensing of even rather big analytes by simple optical means, or even by the bare eye.},
  language  = {en}
}
@article{BogomolovaSeckerKoetzetal.2017,
  author    = {Bogomolova, Anna and Secker, Christian and Koetz, Joachim and Schlaad, Helmut},
  title     = {Thermo-induced multistep assembly of double-hydrophilic block copolypeptoids in water},
  series = {Colloid and polymer science : official journal of the Kolloid-Gesellschaft},
  volume    = {295},
  journal   = {Colloid and polymer science : official journal of the Kolloid-Gesellschaft},
  publisher = {Springer},
  address   = {New York},
  issn      = {0303-402X},
  doi       = {10.1007/s00396-017-4044-6},
  pages     = {1305 -- 1312},
  year      = {2017},
  abstract  = {The aqueous solution behavior of thermoresponsive-hydrophilic block copolypeptoids, i.e., poly(N-(n-propyl)glycine) (x) -block-poly(N-methylglycine) (y) (x = 70; y = 23, 42, 76), in the temperature range of 20-45 A degrees C is studied. Turbidimetric analyses of the 0.1 wt\% aqueous solutions reveal two cloud points at T (cp)similar to 30 and 45 A degrees C and a clearing point in between at T (cl)similar to 42 A degrees C. Temperature-dependent dynamic light scattering (DLS) suggest that right above the first collapse temperature, single polymer molecules assemble into large structures which upon further heating, i.e., at the clearing point temperature, disassemble into micelle-like structures. Upon further heating, the aggregates start to grow again in size, as recognized by the second cloud point, through a crystallization process.},
  language  = {en}
}
@article{SeckerVoelkelTierschetal.2016,
  author    = {Secker, Christian and Voelkel, Antje and Tiersch, Brigitte and Koetz, Joachim and Schlaad, Helmut},
  title     = {Thermo-Induced Aggregation and Crystallization of Block Copolypeptoids in Water},
  series = {Macromolecules : a publication of the American Chemical Society},
  volume    = {49},
  journal   = {Macromolecules : a publication of the American Chemical Society},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0024-9297},
  doi       = {10.1021/acs.macromol.5b02481},
  pages     = {979 -- 985},
  year      = {2016},
  abstract  = {Block copolypeptoids comprising a thermosensitive, crystallizable poly(N-(n-propyl)glycine) block and a watersoluble poly(N-methylglycine) block, P70My (y = 23, 42, 76, 153, and 290), were synthesized bY ring-opening polymerization of the corresponding N-alkylglycine N-carboxyanhydrides (NCAs) and examined according to their thermo-induced aggregation and crystallization in water by turbidimetty, micro-differential scanning calorimetry (micro-DSC); cryogenic scanning electron microscopy (cryo-SEM), analytical ultracentrifugation (AUC), and static light scattering (SLS). At a temperature above the cloud point temperature, the initially formed micellar aggregates started to crystallize and grow into larger complex assemblies of about 100-500 nm, exhibiting flower-like (P70M23), ellipsoidal (P70M42 and P70M72) or irregular shapes (P70M153 and.P70M290).},
  language  = {en}
}
@article{SchwarzSieversBodenthinetal.2010,
  author    = {Schwarz, Guntram and Sievers, Torsten K. and Bodenthin, Yves and Hasslauer, Ires and Geue, Thomas and Koetz, Joachim and Kurth, Dirk G.},
  title     = {The structure of metallo-supramolecular polyelectrolytes in solution and on surfaces},
  issn      = {0959-9428},
  doi       = {10.1039/B926783b},
  year      = {2010},
  abstract  = {Metal ion induced self-assembly of the rigid ligand 1,4-bis(2,2':6',2 ''-terpyridine- 4'-yl) benzene (1) with Fe(II), Co(II), Ni(II) and Zn(II) acetate in aqueous solution results in extended, rigid- rod like metallosupramolecular coordination polyelectrolytes (MEPE-1). Under the current experimental conditions the molar masses range from 1000 g mol(-1) up to 500 000 g mol(-1). The molar mass depends on concentration, stoichiometry, metal-ion and time. In addition, we present viscosity measurements, small angle neutron scattering and AFM data. We introduce a protocol to precisely control the stoichiometry during self-assembly using conductometry. The protocol can be used with different terpyridine ligands and the above-mentioned metal ions and is of paramount importance to obtain meaningful and reproducible results. As a control experiment we studied the mononuclear 4'- (phenyl)2,2':6',2 ''-terpyridine (3) complex with Ni(II) and Zn(II) and the flexible ligand 1,3- bis[4'-oxa(2,2': 6',2 ''-terpyridinyl)] propane (2) with Ni(II) acetate (Ni-MEPE-2). This ligand does not form extended macroassemblies but likely ring-like structures with 3 to 4 repeat units. Through spin- coating of Ni-MEPE-1 on a solid surface we can image the MEPEs in real space by AFM. SANS measurements of Fe-MEPE-1 verify the extended rigid-rod type structure of the MEPEs in aqueous solution.},
  language  = {en}
}
@article{KoetzBeitz1997,
  author    = {Koetz, Joachim and Beitz, Toralf},
  title     = {The phase behaviour of polyanion-polycation systems},
  year      = {1997},
  language  = {en}
}
@article{RuppeltKoetzJaegeretal.1997,
  author    = {Ruppelt, Dirk and Koetz, Joachim and Jaeger, Werner and Friberg, Stig E. and Mackay, R. A.},
  title     = {The influence of cationic polyelectrolytes on structure formation in lamellar liquid crystalline systems},
  year      = {1997},
  language  = {en}
}
@article{KoetzBahnemannKosmella2004,
  author    = {Koetz, Joachim and Bahnemann, Jennifa and Kosmella, Sabine},
  title     = {The influence of a cationic polyelectrolyte on the inverse micellar region of the ternary system sulfobetaine/ water/alcohol},
  issn      = {0887-624X -},
  year      = {2004},
  language  = {en}
}
@article{SarhanKoopmanSchuetzetal.2019,
  author    = {Sarhan, Radwan Mohamed and Koopman, Wouter-Willem Adriaan and Schuetz, Roman and Schmid, Thomas and Liebig, Ferenc and Koetz, Joachim and Bargheer, Matias},
  title     = {The importance of plasmonic heating for the plasmondriven photodimerization of 4-nitrothiophenol},
  series = {Scientific Reports},
  volume    = {9},
  journal   = {Scientific Reports},
  publisher = {Macmillan Publishers Limited},
  address   = {London},
  issn      = {2045-2322},
  doi       = {10.1038/s41598-019-38627-2},
  pages     = {8},
  year      = {2019},
  abstract  = {Metal nanoparticles form potent nanoreactors, driven by the optical generation of energetic electrons and nanoscale heat. The relative influence of these two factors on nanoscale chemistry is strongly debated. This article discusses the temperature dependence of the dimerization of 4-nitrothiophenol (4-NTP) into 4,4′-dimercaptoazobenzene (DMAB) adsorbed on gold nanoflowers by Surface-Enhanced Raman Scattering (SERS). Raman thermometry shows a significant optical heating of the particles. The ratio of the Stokes and the anti-Stokes Raman signal moreover demonstrates that the molecular temperature during the reaction rises beyond the average crystal lattice temperature of the plasmonic particles. The product bands have an even higher temperature than reactant bands, which suggests that the reaction proceeds preferentially at thermal hot spots. In addition, kinetic measurements of the reaction during external heating of the reaction environment yield a considerable rise of the reaction rate with temperature. Despite this significant heating effects, a comparison of SERS spectra recorded after heating the sample by an external heater to spectra recorded after prolonged illumination shows that the reaction is strictly photo-driven. While in both cases the temperature increase is comparable, the dimerization occurs only in the presence of light. Intensity dependent measurements at fixed temperatures confirm this finding.},
  language  = {en}
}
@misc{SarhanKoopmanSchuetzetal.2018,
  author    = {Sarhan, Radwan Mohamed and Koopman, Wouter-Willem Adriaan and Schuetz, Roman and Schmid, Thomas and Liebig, Ferenc and Koetz, Joachim and Bargheer, Matias},
  title     = {The importance of plasmonic heating for the plasmondriven photodimerization of 4-nitrothiophenol},
  series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe},
  number    = {698},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-42719},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427197},
  pages     = {8},
  year      = {2018},
  abstract  = {Metal nanoparticles form potent nanoreactors, driven by the optical generation of energetic electrons and nanoscale heat. The relative influence of these two factors on nanoscale chemistry is strongly debated. This article discusses the temperature dependence of the dimerization of 4-nitrothiophenol (4-NTP) into 4,4′-dimercaptoazobenzene (DMAB) adsorbed on gold nanoflowers by Surface-Enhanced Raman Scattering (SERS). Raman thermometry shows a significant optical heating of the particles. The ratio of the Stokes and the anti-Stokes Raman signal moreover demonstrates that the molecular temperature during the reaction rises beyond the average crystal lattice temperature of the plasmonic particles. The product bands have an even higher temperature than reactant bands, which suggests that the reaction proceeds preferentially at thermal hot spots. In addition, kinetic measurements of the reaction during external heating of the reaction environment yield a considerable rise of the reaction rate with temperature. Despite this significant heating effects, a comparison of SERS spectra recorded after heating the sample by an external heater to spectra recorded after prolonged illumination shows that the reaction is strictly photo-driven. While in both cases the temperature increase is comparable, the dimerization occurs only in the presence of light. Intensity dependent measurements at fixed temperatures confirm this finding.},
  language  = {en}
}
@article{Koetz2020,
  author    = {Koetz, Joachim},
  title     = {The Effect of Surface Modification of Gold Nanotriangles for Surface-Enhanced Raman Scattering Performance},
  series = {Nanomaterials},
  volume    = {10},
  journal   = {Nanomaterials},
  number    = {11},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2079-4991},
  doi       = {10.3390/nano10112187},
  pages     = {13},
  year      = {2020},
  abstract  = {A surface modification of ultraflat gold nanotriangles (AuNTs) with different shaped nanoparticles is of special relevance for surface-enhanced Raman scattering (SERS) and the photo-catalytic activity of plasmonic substrates. Therefore, different approaches are used to verify the flat platelet morphology of the AuNTs by oriented overgrowth with metal nanoparticles. The most important part for the morphological transformation of the AuNTs is the coating layer, containing surfactants or polymers. By using well established AuNTs stabilized by a dioctyl sodium sulfosuccinate (AOT) bilayer, different strategies of surface modification with noble metal nanoparticles are possible. On the one hand undulated superstructures were synthesized by in situ growth of hemispherical gold nanoparticles in the polyethyleneimine (PEI)-coated AOT bilayer of the AuNTs. On the other hand spiked AuNTs were obtained by a direct reduction of Au³⁺ ions in the AOT double layer in presence of silver ions and ascorbic acid as reducing agent. Additionally, crumble topping of the smooth AuNTs can be realized after an exchange of the AOT bilayer by hyaluronic acid, followed by a silver-ion mediated reduction with ascorbic acid. Furthermore, a decoration with silver nanoparticles after coating the AOT bilayer with the cationic surfactant benzylhexadecyldimethylammonium chloride (BDAC) can be realized. In that case the ultraviolet (UV)-absorption of the undulated Au@Ag nanoplatelets can be tuned depending on the degree of decoration with silver nanoparticles. Comparing the Raman scattering data for the plasmon driven dimerization of 4-nitrothiophenol (4-NTP) to 4,4′-dimercaptoazobenzene (DMAB) one can conclude that the most important effect of surface modification with a 75 times higher enhancement factor in SERS experiments becomes available by decoration with gold spikes.},
  language  = {en}
}
@misc{Koetz2020,
  author    = {Koetz, Joachim},
  title     = {The Effect of Surface Modification of Gold Nanotriangles for Surface-Enhanced Raman Scattering Performance},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {1022},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-48517},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-485172},
  pages     = {15},
  year      = {2020},
  abstract  = {A surface modification of ultraflat gold nanotriangles (AuNTs) with different shaped nanoparticles is of special relevance for surface-enhanced Raman scattering (SERS) and the photo-catalytic activity of plasmonic substrates. Therefore, different approaches are used to verify the flat platelet morphology of the AuNTs by oriented overgrowth with metal nanoparticles. The most important part for the morphological transformation of the AuNTs is the coating layer, containing surfactants or polymers. By using well established AuNTs stabilized by a dioctyl sodium sulfosuccinate (AOT) bilayer, different strategies of surface modification with noble metal nanoparticles are possible. On the one hand undulated superstructures were synthesized by in situ growth of hemispherical gold nanoparticles in the polyethyleneimine (PEI)-coated AOT bilayer of the AuNTs. On the other hand spiked AuNTs were obtained by a direct reduction of Au³⁺ ions in the AOT double layer in presence of silver ions and ascorbic acid as reducing agent. Additionally, crumble topping of the smooth AuNTs can be realized after an exchange of the AOT bilayer by hyaluronic acid, followed by a silver-ion mediated reduction with ascorbic acid. Furthermore, a decoration with silver nanoparticles after coating the AOT bilayer with the cationic surfactant benzylhexadecyldimethylammonium chloride (BDAC) can be realized. In that case the ultraviolet (UV)-absorption of the undulated Au@Ag nanoplatelets can be tuned depending on the degree of decoration with silver nanoparticles. Comparing the Raman scattering data for the plasmon driven dimerization of 4-nitrothiophenol (4-NTP) to 4,4′-dimercaptoazobenzene (DMAB) one can conclude that the most important effect of surface modification with a 75 times higher enhancement factor in SERS experiments becomes available by decoration with gold spikes.},
  language  = {en}
}
@article{WellertTierschKoetzetal.2011,
  author    = {Wellert, Stefan and Tiersch, Brigitte and Koetz, Joachim and Richardt, Andre and Lapp, Alain and Holderer, Olaf and Gaeb, Juergen and Blum, Marc-Michael and Schulreich, Christoph and Stehle, Ralf and Hellweg, Thomas},
  title     = {The DFPase from Loligo vulgaris in sugar surfactant-based bicontinuous microemulsions structure, dynamics, and enzyme activity},
  series = {European biophysics journal : with biophysics letters ; an international journal of biophysics},
  volume    = {40},
  journal   = {European biophysics journal : with biophysics letters ; an international journal of biophysics},
  number    = {6},
  publisher = {Springer},
  address   = {New York},
  issn      = {0175-7571},
  doi       = {10.1007/s00249-011-0689-0},
  pages     = {761 -- 774},
  year      = {2011},
  abstract  = {The enzyme diisopropyl fluorophosphatase (DFPase) from the squid Loligo vulgaris is of great interest because of its ability to catalyze the hydrolysis of highly toxic organophosphates. In this work, the enzyme structure in solution (native state) was studied by use of different scattering methods. The results are compared with those from hydrodynamic model calculations based on the DFPase crystal structure. Bicontinuous microemulsions made of sugar surfactants are discussed as host systems for the DFPase. The microemulsion remains stable in the presence of the enzyme, which is shown by means of scattering experiments. Moreover, activity assays reveal that the DFPase still has high activity in this complex reaction medium. To complement the scattering experiments cryo-SEM was also employed to study the microemulsion structure.},
  language  = {en}
}
@article{KosmellaKoetzShirahamaetal.1998,
  author    = {Kosmella, Sabine and Koetz, Joachim and Shirahama, K. and Liu, J.},
  title     = {The cooperative nature of complex formation in mixed polyelectrolyte-surfactant systems},
  year      = {1998},
  language  = {en}
}
@article{FortesMartinPrietzelKoetz2021,
  author    = {Fortes Mart{\´i}n, Rebeca and Prietzel, Claudia Christina and Koetz, Joachim},
  title     = {Template-mediated self-assembly of magnetite-gold nanoparticle superstructures at the water-oil interface of AOT reverse microemulsions},
  series = {Journal of colloid and interface science},
  volume    = {581},
  journal   = {Journal of colloid and interface science},
  number    = {Part A},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0021-9797},
  doi       = {10.1016/j.jcis.2020.07.079},
  pages     = {44 -- 55},
  year      = {2021},
  abstract  = {Hypothesis: Bimetallic magnetite-gold nanostructures are interesting candidates to combine and enhance individual properties of each metal element in catalytic and analytical applications. Microemulsions have been employed in templated synthesis of nanoparticles, and their combination with different types of nanoparticles can further mediate interactions at the water-oil interface, providing new forms of hybrid nanostructures. Experiments: Reverse water-in-oil microemulsions of droplet sizes below 50 nm were prepared from ternary mixtures of Aerosol-OT (AOT) as surfactant, incorporating 4 nm sized superparamagnetic nanoparticles (MNPs) to the hexane-pentanol oil phase and 5 nmsized polyethyleneimine-stabilized gold nanoparticles (Au(PEI)-NPs) to the water phase. The resulting isotropic L-2 phase, Winsor phases and organized nanostructures were investigated using conductometry, calorimetry, UV-Vis spectroscopy, cryoSEM and HRTEM. Findings: Droplet-droplet interactions, morphology and surfactant film properties of AOT microemulsions could be modulated in different ways by the presence of the different nanoparticles from each liquid phase. Additionally, phase separation into Winsor phases allows the formation upon solvent evaporation of films with bimetallic heterostructures on the micrometer scale. This demonstrates a new way of nanoparticle templated assembly at liquid interfaces by assisted interactions between microemulsions and nanoparticles, as a promising strategy to obtain thin films of small, isotropic nanoparticles with hierarchical ordering.},
  language  = {en}
}
@misc{RajuLiebigHessetal.2019,
  author    = {Raju, Rajarshi Roy and Liebig, Ferenc and Hess, Andreas and Schlaad, Helmut and Koetz, Joachim},
  title     = {Temperature-triggered reversible breakdown of polymer-stabilized olive},
  series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe},
  number    = {751},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-43646},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-436461},
  pages     = {19271 -- 19277},
  year      = {2019},
  abstract  = {A one-step moderate energy vibrational emulsification method was successfully employed to produce thermo-responsive olive/silicone-based Janus emulsions stabilized by poly(N,N-diethylacrylamide) carrying 0.7 mol\% oleoyl side chains. Completely engulfed emulsion droplets remained stable at room temperature and could be destabilized on demand upon heating to the transition temperature of the polymeric stabilizer. Time-dependent light micrographs demonstrate the temperature-induced breakdown of the Janus droplets, which opens new aspects of application, for instance in biocatalysis.},
  language  = {en}
}
@article{RajuLiebigHessetal.2019,
  author    = {Raju, Rajarshi Roy and Liebig, Ferenc and Hess, Andreas and Schlaad, Helmut and Koetz, Joachim},
  title     = {Temperature-triggered reversible breakdown of polymer-stabilized olive},
  series = {RSC Advances},
  volume    = {9},
  journal   = {RSC Advances},
  number    = {35},
  publisher = {RSC Publishing},
  address   = {London},
  issn      = {2046-2069},
  doi       = {10.1039/c9ra03463c},
  pages     = {19271 -- 19277},
  year      = {2019},
  abstract  = {A one-step moderate energy vibrational emulsification method was successfully employed to produce thermo-responsive olive/silicone-based Janus emulsions stabilized by poly(N,N-diethylacrylamide) carrying 0.7 mol\% oleoyl side chains. Completely engulfed emulsion droplets remained stable at room temperature and could be destabilized on demand upon heating to the transition temperature of the polymeric stabilizer. Time-dependent light micrographs demonstrate the temperature-induced breakdown of the Janus droplets, which opens new aspects of application, for instance in biocatalysis.},
  language  = {en}
}
@article{HellwegBruletLappetal.2002,
  author    = {Hellweg, Thomas and Brulet, Anni and Lapp, A. and Robertson, Daniela and Koetz, Joachim},
  title     = {Temperature and polymer induced structural changes in SDS/decanol based multilamellar vesicles},
  year      = {2002},
  language  = {en}
}
@article{KoethTierschAppelhansetal.2012,
  author    = {Koeth, Anja and Tiersch, Brigitte and Appelhans, Dietmar and Gradzielski, Michael and C{\"o}lfen, Helmut and Koetz, Joachim},
  title     = {Synthesis of Core-Shell Gold Nanoparticles with Maltose-Modified Poly(Ethyleneimine)},
  series = {Journal of dispersion science and technology},
  volume    = {33},
  journal   = {Journal of dispersion science and technology},
  number    = {1-3},
  publisher = {Taylor \& Francis Group},
  address   = {Philadelphia},
  issn      = {0193-2691},
  doi       = {10.1080/01932691.2010.530084},
  pages     = {52 -- 60},
  year      = {2012},
  abstract  = {The synthesis of ultrafine gold nanoparticles in presence of maltose-modified hyperbranched poly(ethyleneimines) (PEI) is described. The polymer acted as both a reducing and stabilising agent in the particle formation process. The nanoparticles were characterized by means of dynamic light scattering (DLS), transmission electron microscopy (TEM), analytical ultracentrifugation (AUC), small-angle x-ray scattering (SAXS), and small-angle neutron scattering (SANS). The mechanism of nanoparticle formation can be described in two steps. The reduction process of the Au3+ ions located in the inner coil region of the hyperbranched PEI led to the formation of a compact gold core, and is accompanied by a collapse of the polymer coil. Therefore, in the subsequent reduction process a gold-polymer hybrid shell is formed. By using the PEI of higher molar mass, core-shell gold nanoparticles of about 3.6 nm size with a more narrow size distribution and special fluorescence behavior could be synthesized.},
  language  = {en}
}
@article{IhlenburgMaiThuenemannetal.2021,
  author    = {Ihlenburg, Ramona and Mai, Tobias and Th{\"u}nemann, Andreas F. and Baerenwald, Ruth and Saalw{\"a}chter, Kay and Koetz, Joachim and Taubert, Andreas},
  title     = {Sulfobetaine hydrogels with a complex multilength-scale hierarchical structure},
  series = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry},
  volume    = {125},
  journal   = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry},
  number    = {13},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1520-6106},
  doi       = {10.1021/acs.jpcb.0c10601},
  pages     = {3398 -- 3408},
  year      = {2021},
  abstract  = {Hydrogels with a hierarchical structure were prepared from a new highly water-soluble crosslinker N,N,N',N'-tetramethyl-N,N'-bis(2-ethylmethacrylate)-propyl-1,3-diammonium dibromide and from the sulfobetaine monomer 2-(N-3-sulfopropyl-N,N-dimethyl ammonium)ethyl methacrylate. The free radical polymerization of the two compounds is rapid and yields near-transparent hydrogels with sizes up to 5 cm in diameter. Rheology shows a clear correlation between the monomer-to-crosslinker ratio and the storage and loss moduli of the hydrogels. Cryo-scanning electron microscopy, low-field nuclear magnetic resonance (NMR) spectroscopy, and small-angle X-ray scattering show that the gels have a hierarchical structure with features spanning the nanometer to the sub-millimeter scale. The NMR study is challenged by the marked inhomogeneity of the gels and the complex chemical structure of the sulfobetaine monomer. NMR spectroscopy shows how these complications can be addressed via a novel fitting approach that considers the mobility gradient along the side chain of methacrylate-based monomers.},
  language  = {en}
}
@article{IhlenburgLehnenKoetzetal.2021,
  author    = {Ihlenburg, Ramona and Lehnen, Anne-Catherine and Koetz, Joachim and Taubert, Andreas},
  title     = {Sulfobetaine Cryogels for Preferential Adsorption of Methyl Orange from Mixed Dye Solutions},
  series = {Polymers / Molecular Diversity Preservation International},
  volume    = {13},
  journal   = {Polymers / Molecular Diversity Preservation International},
  number    = {2},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2073-4360},
  doi       = {10.3390/polym13020208},
  pages     = {11},
  year      = {2021},
  abstract  = {New cryogels for selective dye removal from aqueous solution were prepared by free radical polymerization from the highly water-soluble crosslinker N,N,N',N'-tetramethyl-N,N'-bis(2-ethylmethacrylate)-propyl-1,3-diammonium dibromide and the sulfobetaine monomer 2-(N-3-sulfopropyl-N,N-dimethyl ammonium)ethyl methacrylate. The resulting white and opaque cryogels have micrometer sized pores with a smaller substructure. They adsorb methyl orange (MO) but not methylene blue (MB) from aqueous solution. Mixtures of MO and MB can be separated through selective adsorption of the MO to the cryogels while the MB remains in solution. The resulting cryogels are thus candidates for the removal of hazardous organic substances, as exemplified by MO and MB, from water. Clearly, it is possible that the cryogels are also potentially interesting for removal of other compounds such as pharmaceuticals or pesticides, but this must be investigated further.},
  language  = {en}
}
@misc{IhlenburgLehnenKoetzetal.2021,
  author    = {Ihlenburg, Ramona and Lehnen, Anne-Catherine and Koetz, Joachim and Taubert, Andreas},
  title     = {Sulfobetaine Cryogels for Preferential Adsorption of Methyl Orange from Mixed Dye Solutions},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {1093},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-48898},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-488987},
  pages     = {13},
  year      = {2021},
  abstract  = {New cryogels for selective dye removal from aqueous solution were prepared by free radical polymerization from the highly water-soluble crosslinker N,N,N',N'-tetramethyl-N,N'-bis(2-ethylmethacrylate)-propyl-1,3-diammonium dibromide and the sulfobetaine monomer 2-(N-3-sulfopropyl-N,N-dimethyl ammonium)ethyl methacrylate. The resulting white and opaque cryogels have micrometer sized pores with a smaller substructure. They adsorb methyl orange (MO) but not methylene blue (MB) from aqueous solution. Mixtures of MO and MB can be separated through selective adsorption of the MO to the cryogels while the MB remains in solution. The resulting cryogels are thus candidates for the removal of hazardous organic substances, as exemplified by MO and MB, from water. Clearly, it is possible that the cryogels are also potentially interesting for removal of other compounds such as pharmaceuticals or pesticides, but this must be investigated further.},
  language  = {en}
}
@article{KoetzKosmella1995,
  author    = {Koetz, Joachim and Kosmella, Sabine},
  title     = {Structured pigments due to polyelectro lyte complex formation},
  year      = {1995},
  language  = {en}
}
@article{BechtholdTierschKoetzetal.1999,
  author    = {Bechthold, Nina and Tiersch, Brigitte and Koetz, Joachim and Friberg, Stig E.},
  title     = {Structure Formation in polymer-modified liquid crystals},
  year      = {1999},
  language  = {en}
}
@article{SchwarzBodenthinGeueetal.2010,
  author    = {Schwarz, Guntram and Bodenthin, Yves and Geue, Thomas and Koetz, Joachim and Kurth, Dirk G.},
  title     = {Structure and properties of dynamic rigid rod-like metallo-supramolecular polyelectrolytes in solution},
  issn      = {0024-9297},
  doi       = {10.1021/Ma902057f},
  year      = {2010},
  abstract  = {Metal-ion-induced self-assembly in aqueous solution of the rigid ligand 1,4-bis(2,2':6',2 ''-terpyridine-4'-yl)benzene (1) with Fe(OAc)(2) and Ni(OAc)(2) is investigated with viscosimetry, SANS, and AFM. Ligand 1 forms extended, rigid-rod like metallo-supramolecular coordination polyeectrolytes (MEPEs) with a molar mass of up to 200 000 g mol(-1) under the Current experimental conditions. The molar mass depends oil concentration, stoichiometry, and time. By spin-coating MEPEs oil a solid surface, we call image the MEPEs in real space by AFM. Both AFM and SANS confirm the extended rigid-rod-type structure of the MEPEs. As a control experiment, we also studied the flexible ligand 1,3-bis[4'-oxa(2,2':6',2 ''-terpyridinyl)]propane (2). Ligand 2 does not form extended macro-assemblies but likely ringlike structures with three 10 four repeat units. Finally, we present it protocol to control the stoichiometry during self-assembly using conductometry, which is of paramount importance to obtain meaningful and reproducible results.},
  language  = {en}
}
@article{RojasKoetzKosmellaetal.2009,
  author    = {Rojas, Oscar and Koetz, Joachim and Kosmella, Sabine and Tiersch, Brigitte and Wacker, Philipp and Kramer, Markus},
  title     = {Structural studies of ionic liquid-modified microemulsions},
  issn      = {0021-9797},
  doi       = {10.1016/j.jcis.2009.02.039},
  year      = {2009},
  abstract  = {This work is focused on the influence of an ionic liquid (IL), i.e. ethyl-methylimidazolium hexylsulfate, on the spontaneous formation of microemulsions with ionic surfactants. The influence of the ionic liquid on Structure formation in the optically clear phase region in water/toluene/pentanol mixtures in presence of the cationic surfactant CTAB was studied in more detail. The results show a significant increase of the transparent phase region by adding the ionic liquid. Conductometric investigations demonstrate that adding the ionic liquid can drastically reduce the droplet- droplet interactions in the L-2 phase. H-1 nuclear magnetic resonance (H-1 NMR) diffusion coefficient measurements in combination with dynamic light scattering measurements clearly show that inverse microemulsion droplets still exist, but the droplet size is decreased to 2 nm. A more detailed characterisation of the isotropic phase channel by means of conductivity measurements, dynamic light scattering (DLS), H-1 NMR and cryo-scanning electron microscopy (SEM), allows the identification of a bicontinuous sponge phase between the L-1 and L-2 phase. When the poly(ethyleneimine) is added, the isotropic phase range is reduced drastically, but the inverse microemulsion range still exists.},
  language  = {en}
}
@article{NoteKoetzKosmella2006,
  author    = {Note, Carine and Koetz, Joachim and Kosmella, Sabine},
  title     = {Structural changes in poly(ethyleneimine) modified microemulsion},
  series = {Journal of colloid and interface science},
  volume    = {302},
  journal   = {Journal of colloid and interface science},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0021-9797},
  doi       = {10.1016/j.jcis.2006.06.071},
  pages     = {662 -- 668},
  year      = {2006},
  abstract  = {The influence of branched poly(ethyleneimine) on the phase behavior of the system sodium dodecylsulfate/toluene-pentanol (1:1)/water has been studied. The isotropic microemulsions still exist when water is replaced with aqueous solutions of PEI (up to 30\% in weight), but their stability is significantly influenced. From a polymer concentration of 20 wt\%, the polymer enhances the solubilization of water in oil, changes the sign of the spontaneous curvature of the surfactant film, and induces an inversion of the microemulsion type from water-in-oil (L-2) to oil-in-water (L-1), by the formation of a bicontinuous channel. Further investigations show that the addition of polymer in the L-2 phase changes the droplet-droplet interactions as the conductivity drops and the percolation disappears. In the bicontinuous channel, higher viscosities can be detected, as well as a weak percolation followed by a steep increase of the conductivity, which can be related to evident structural changes in the system. DSC measurements allow then to follow the changes of the water properties in the system, from interfacial-water in the L-2 phase to free-water in the sponge-like phase. Finally, all the measurements performed permit to characterize the structural transitions in the system and to understand the role of the added polymer.},
  language  = {en}
}
@article{TierschKoetzHartmann1997,
  author    = {Tiersch, Brigitte and Koetz, Joachim and Hartmann, J{\"u}rgen},
  title     = {Structural Analysis of the influence of polymers on lyotropic liquid-crystal systems},
  year      = {1997},
  language  = {en}
}
@article{DautzenbergKoetzRotheretal.1994,
  author    = {Dautzenberg, Herbert and Koetz, Joachim and Rother, G. and Philipp, B. and Rother, G.},
  title     = {Static light scattering of polyelectrolyte complex solutions},
  year      = {1994},
  language  = {en}
}
@article{HeinzeHeinzeGrotheetal.2001,
  author    = {Heinze, Thomas and Heinze, Ute and Grothe, Carsten and Koetz, Joachim and Lazik, Waldemar},
  title     = {Starch derivatives of high degree of functionalization : 4. Homogeneous tritylation of starch an subsequent carboxymethylation},
  year      = {2001},
  language  = {en}
}
@misc{LiebigSarhanBargheeretal.2020,
  author    = {Liebig, Ferenc and Sarhan, Radwan Mohamed and Bargheer, Matias and Schmitt, Clemens Nikolaus Zeno and Poghosyan, Armen H. and Shahinyanf, Aram A. and Koetz, Joachim},
  title     = {Spiked gold nanotriangles},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
  number    = {829},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-44556},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-445568},
  pages     = {11},
  year      = {2020},
  abstract  = {We show the formation of metallic spikes on the surface of gold nanotriangles (AuNTs) by using the same reduction process which has been used for the synthesis of gold nanostars. We confirm that silver nitrate operates as a shape-directing agent in combination with ascorbic acid as the reducing agent and investigate the mechanism by dissecting the contribution of each component, i.e., anionic surfactant dioctyl sodium sulfosuccinate (AOT), ascorbic acid (AA), and AgNO3. Molecular dynamics (MD) simulations show that AA attaches to the AOT bilayer of nanotriangles, and covers the surface of gold clusters, which is of special relevance for the spike formation process at the AuNT surface. The surface modification goes hand in hand with a change of the optical properties. The increased thickness of the triangles and a sizeable fraction of silver atoms covering the spikes lead to a blue-shift of the intense near infrared absorption of the AuNTs. The sponge-like spiky surface increases both the surface enhanced Raman scattering (SERS) cross section of the particles and the photo-catalytic activity in comparison with the unmodified triangles, which is exemplified by the plasmon-driven dimerization of 4-nitrothiophenol (4-NTP) to 4,4'-dimercaptoazobenzene (DMAB).},
  language  = {en}
}
@article{LiebigSarhanBargheeretal.2020,
  author    = {Liebig, Ferenc and Sarhan, Radwan Mohamed and Bargheer, Matias and Schmitt, Clemens Nikolaus Zeno and Poghosyan, Armen H. and Shahinyanf, Aram A. and Koetz, Joachim},
  title     = {Spiked gold nanotriangles},
  series = {RSC Advances},
  volume    = {10},
  journal   = {RSC Advances},
  number    = {14},
  publisher = {RSC Publishing},
  address   = {London},
  issn      = {2046-2069},
  doi       = {10.1039/d0ra00729c},
  pages     = {8152 -- 8160},
  year      = {2020},
  abstract  = {We show the formation of metallic spikes on the surface of gold nanotriangles (AuNTs) by using the same reduction process which has been used for the synthesis of gold nanostars. We confirm that silver nitrate operates as a shape-directing agent in combination with ascorbic acid as the reducing agent and investigate the mechanism by dissecting the contribution of each component, i.e., anionic surfactant dioctyl sodium sulfosuccinate (AOT), ascorbic acid (AA), and AgNO3. Molecular dynamics (MD) simulations show that AA attaches to the AOT bilayer of nanotriangles, and covers the surface of gold clusters, which is of special relevance for the spike formation process at the AuNT surface. The surface modification goes hand in hand with a change of the optical properties. The increased thickness of the triangles and a sizeable fraction of silver atoms covering the spikes lead to a blue-shift of the intense near infrared absorption of the AuNTs. The sponge-like spiky surface increases both the surface enhanced Raman scattering (SERS) cross section of the particles and the photo-catalytic activity in comparison with the unmodified triangles, which is exemplified by the plasmon-driven dimerization of 4-nitrothiophenol (4-NTP) to 4,4'-dimercaptoazobenzene (DMAB).},
  language  = {en}
}
@article{GrosskopfTierschKoetzetal.2019,
  author    = {Großkopf, S{\"o}ren and Tiersch, Brigitte and Koetz, Joachim and Mix, Andreas and Hellweg, Thomas},
  title     = {Shear-Induced Transformation of Polymer-Rich Lamellar Phases to Micron-Sized Vesicles},
  series = {Langmuir},
  volume    = {35},
  journal   = {Langmuir},
  number    = {8},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0743-7463},
  doi       = {10.1021/acs.langmuir.8602786},
  pages     = {3048 -- 3057},
  year      = {2019},
  abstract  = {In the present work, we study the shear-induced transformation of polymer-rich lamellar phases into vesicles. The evolution of vesicle size is studied by different scattering techniques, rheology, and microscopy methods. The lamellar phase found in the system D2O/o-xylene/Pluronic PE9400/C(8)TAB can be fully transformed to multilamellar vesicles (MLVs) by applying shear. The size of the MLVs is proportional to the inverse square root of the shear rate. Hence, the polymer based quaternary system behaves similar to lamellar phases based on small surfactant molecules. Additionally, we found a growth effect leading to a size increase of the vesicles after shearing was stopped.},
  language  = {en}
}
@article{KoetzKosmellaBruehl1996,
  author    = {Koetz, Joachim and Kosmella, Sabine and Br{\"u}hl, Iris},
  title     = {Self-assembly of liquid crystalline lamellar surfactant-polyelectrolyte systems},
  year      = {1996},
  language  = {en}
}
@article{Koetz1997,
  author    = {Koetz, Joachim},
  title     = {Self-assembled polymer-surfactant systems},
  year      = {1997},
  language  = {en}
}
@article{KoetzKosmellaBeitz2001,
  author    = {Koetz, Joachim and Kosmella, Sabine and Beitz, Toralf},
  title     = {Self-assembled Polyelectrolyte Systems},
  year      = {2001},
  language  = {en}
}
@article{KoetzPlantenberg1998,
  author    = {Koetz, Joachim and Plantenberg, Thomas},
  title     = {Self-assembled polyanion-polycation systems},
  isbn      = {0-9585708-1-7},
  year      = {1998},
  language  = {en}
}
@article{PoghosyanShahinyanKoetz2018,
  author    = {Poghosyan, Armen H. and Shahinyan, A. A. and Koetz, Joachim},
  title     = {Self-assembled monolayer formation of distorted cylindrical AOT micelles on gold surfaces},
  series = {Colloids and surfaces : an international journal devoted to the principles and applications of colloid and interface science ; A, Physicochemical and engineering aspects},
  volume    = {546},
  journal   = {Colloids and surfaces : an international journal devoted to the principles and applications of colloid and interface science ; A, Physicochemical and engineering aspects},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0927-7757},
  doi       = {10.1016/j.colsurfa.2018.02.067},
  pages     = {20 -- 27},
  year      = {2018},
  abstract  = {Self-assembling features of sodium dioctyl sulfosuccinate (AOT) molecules and micelle adsorption on gold Au (111) surfaces have been examined using molecular dynamics simulation. We argue that AOT micelles display a strong adsorption on gold surfaces resulting in distorted cylindrical micelles attached to the (111) facets. The well protected Au(111) facets decorated by a dense packed elongated ellipsoidal AOT layer hinder the diffusion of the reactant to the (111) facets and could result in the preferential growth of ultra-thin gold nanoplatelets.},
  language  = {en}
}
@article{KoetzBeitzTiersch1999,
  author    = {Koetz, Joachim and Beitz, Toralf and Tiersch, Brigitte},
  title     = {Self assembled polymer-surfactant systems},
  year      = {1999},
  language  = {en}
}
@article{SarhanKoopmanPudelletal.2019,
  author    = {Sarhan, Radwan Mohamed and Koopman, Wouter-Willem Adriaan and Pudell, Jan-Etienne and Stete, Felix and R{\"o}ssle, Matthias and Herzog, Marc and Schmitt, Clemens Nikolaus Zeno and Liebig, Ferenc and Koetz, Joachim and Bargheer, Matias},
  title     = {Scaling up nanoplasmon catalysis},
  series = {The journal of physical chemistry : C, Nanomaterials and interfaces},
  volume    = {123},
  journal   = {The journal of physical chemistry : C, Nanomaterials and interfaces},
  number    = {14},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1932-7447},
  doi       = {10.1021/acs.jpcc.8b12574},
  pages     = {9352 -- 9357},
  year      = {2019},
  abstract  = {Nanoscale heating by optical excitation of plasmonic nanoparticles offers a new perspective of controlling chemical reactions, where heat is not spatially uniform as in conventional macroscopic heating but strong temperature gradients exist around microscopic hot spots. In nanoplasmonics, metal particles act as a nanosource of light, heat, and energetic electrons driven by resonant excitation of their localized surface plasmon resonance. As an example of the coupling reaction of 4-nitrothiophenol into 4,4′-dimercaptoazobenzene, we show that besides the nanoscopic heat distribution at hot spots, the microscopic distribution of heat dictated by the spot size of the light focus also plays a crucial role in the design of plasmonic nanoreactors. Small sizes of laser spots enable high intensities to drive plasmon-assisted catalysis. This facilitates the observation of such reactions by surface-enhanced Raman scattering, but it challenges attempts to scale nanoplasmonic chemistry up to large areas, where the excess heat must be dissipated by one-dimensional heat transport.},
  language  = {en}
}